1, 2 and 3 Digit Codes: 157

Scan Tool 157 (MIL 11):

Trouble Code Number
- Scan tool 157
- General Scan Tool P1391
- MIL 11

Fault Message
- Intermittent Loss of CMP or CKP

Background
- After the engine has been started, the powertrain control module maintains an expected camshaft port level value.
- At every 69-degree crankshaft leading edge, this value is updated to reflect the expected change in the cam level.
- At every crankshaft trailing edge, this value is compared to the true camshaft port level.
- If there is a disagreement between the two values, then the diagnostic trouble code is set

Range of Check
- Engine: running

Set Condition
- Cam and crank signals have been out of sync. more than 5 times.

Probable Cause
- Camshaft position sensor connector improperly connected
- Crankshaft position sensor connector improperly connected
- Camshaft position sensor related circuit failed
- Crankshaft position sensor related circuit failed
- Camshaft position sensor improperly installed
- Crankshaft position sensor improperly installed